Tech: Cutting down the shaft on the R2 tranny

[Etype R]

The only thing I do not like with the R2 tranny is how long the rear output shaft is. And being that I have brushless motors for both of my R2 trannys, the clearance is less of a issue for me. But at least it is to long, and not to short. We can cut it down to any size we want, and I will show you how I shortened mine.

The first thing you need to do is determine how much you can remove, without your shaft shaft hitting the motor under any extreme angle. Keep in mind that if you end up cutting it to short, you can not add to it, and the gear is pressed on to the shaft. With the gear being a part of the shaft, I can not see this being a cheap part to replace. But if you do end up short and it hits the motor, you could always just stand the tranny up or get a small brushless motor.

Now take the front plate off the tranny by removing the front 4 bolts. Once you have the bolts removed, tap the back of the shaft to loosen the front plate. Now you can see how this tranny was built, pull all the gears out and note the placement of the gears and spacers. We only need the output gear shaft, so put the rest of the parts some place safe for now. I also removed the ball bearings at this time.





Before starting on the shaft, I recommend either making a 5mm collet or buying one to use as a guide. I took a old Tamiya universal joint
and removed the ears from one end.



Now clamp the output shaft into a vice, short end in the vice. Slip the collet over the shaft and measure the length of shaft you wish to remove. On this one I took off 1 inch, only take this much off if you are using a small brushless motor such as the new Holmes Hobbies RR2 motor.



Using a hack saw, cut the output shaft along the collet. The collet acts as a guide and should help you keep the end of the shaft flat. There is no turning back once you start the cut.



Cutting the shaft down shouldn't take to long with a good blade. And the cut should be pretty flat, but you can file it down after cutting it. Here is what it looks like after the cut.



Now we need to add a new flat spot on the output shaft. I opted to make it the same length as the original. To do this I simply slipped the collet back and matched up the orginal flat spot with the collet and cut off shaft.



Now using a Flat Bastard mill file, make flat even passes over the end of the shaft. To save on the life of your file push it forward, then lift it off the shaft and bring it back. Pulling back on the file will only dull it. Also each time you lift the file you can check your progress, making sure it looks even.





And thats it! From here you can take some sand paper and smooth the edges of the shaft. Any grit should work, I used 1200 grit on mine, as it was the first thing I found. After the filing your shaft should look something like this.





Now put the gears back in, this picture might help you with the order of the gears and spacers.



And here it is finished, wasn't to hard was it? And its much cleaner looking now.




And with the Holmes Hobbies RR2 motor I still have plenty of clearance.

[hotwheels000]

good post, it gives you a chance to inspect the tranny also.

If you dont want to inspect the tranny just use a dremal and cut of wheel. You wont apply any undo pressure on the the shaft this way, so there is no need to take it a part and support it.


Edit: be sure and plug all openings so that no debri can enter the tranny

Devlin

[Etype R]

Thanks,

I also found out today that the only way to fit a 14t or larger pinion is to remove the front cover. And you have to use one of the mounting holes to slip a allen wrench in to tighten the set screw.

[LorenzoZ]

i need the pics on this post ... to bad they dont show up anymore :-(

i need to do this on 2 R2HD trans

any help would be good

thanks

[Etype R]

Pictures are back up, I moved my website to another host and still have some files I need to put back up